Any man could, if he were so inclined, be the sculptor of his own brain.

Advice for a Young Investigator (1897), p. xv

There are no small problems. Problems that appear small are large problems that are not understood

Advice for a Young Investigator (1897), p. 17

The history of civilization proves beyond doubt just how sterile the repeated attempts of metaphysics to guess at nature' s laws have been. Instead, there is every reason to believe that when the human intellect ignores reality and concentrates within, it can no longer explain the simplest inner workings of life' s machinery or of the world around us.